PMR on display
PMRExpo, staged each November in Cologne, is Germany’s largest professional communications event. We highlight some of the innovations seen at the show
November’s PMRExpo in Cologne has grown to become Europe’s largest event dedicated to professional and business mobile radio. For 2012, the exhibition hall housed more than 180 stands featuring the biggest names in communications as well as some new ones participating for the first time. Alongside the exhibition, three days of colloquium sessions, presented in German and English with simultaneous translation, offered information, opinion, advice and case studies. This time the programme focused especially on digital, reflecting a growing interest in DMR and dPMR as well as Tetra for private radio systems. There were also updates on Germany’s BOSNet public safety network, the world’s largest Tetra project.
Moving towards a unified solution
An evolution of public safety communications from today’s Tetra mobile radio system towards a unified network solution combining Tetra with LTE was the topic for Richard Bennett on the Motorola Solutions stand.
“Everybody understands why we need Tetra private mobile radio for public safety; everybody understands mission-critical needs, security, resilience, coverage”, he said. “So we are talking about Tetra with TEDS and LTE working together. You create your own secure private data network for public safety and it gives you control of the operations around that network. So as opposed to having a commercial network which you are kind of using for public safety, over-the-top or just having a roaming agreement, it gives you complete control over what is going on.
“If you build a Tetra network now, you need to make sure it’s future-proof, future-ready. And that might mean having a physical network that’s built with LTE and Tetra in mind – you would have dual base station sites, so you have the ability to use the same mast or base site for Tetra and LTE.
“When we talk about public safety LTE, we’re not just talking about a dedicated network. We are talking about a public safety core which gives you the ability to do things like multimedia talk groups, resource tracking – and it gives you the kind of functionality you would expect from a Tetra system. So it’s not just an LTE system – it’s public safety LTE with LTE core.
“Everything you would expect from a Tetra network, you can get from an LTE network with a dedicated public safety LTE core. For example, we have a partnership with Ericsson on LTE. One of my Ericsson colleagues talks about LTE being like a six-lane motorway. If it is commercial LTE, all six lanes could be jam-packed. If you have public safety LTE, you have the ability to put the blue lights on a message, clear the traffic and send it straight through! And that’s why you need a dedicated public safety LTE core.
Already Motorola Solutions is pursuing this approach in the US, where it has been awarded seven of the first nine contracts for public safety LTE deployments. “The one that is probably the most progressed is Harris County, which is Houston, in Texas”, Mr Bennett said. “As I understand it, the urban area is covered by the public safety LTE network whereas the more rural area of the county is covered by Verizon’s LTE network. So it’s about giving you that coverage.
“I see it working that way in most places. You could basically run a Tetra network, implement the public safety LTE core, plug it into a commercial network and then you could add your own dedicated public safety network at a later stage. So there will definitely be an evolution. I think most people will take a commercial network partner first and then build their own dedicated network. I think there’s going to be some caution. And also, spectrum: commercial spectrum is going to be available first.”
Digital radios for front-of-house users
On the DMR side, Motorola featured its compact SL4000 radio, the newest addition to the MotoTrbo product family. “We designed this as an alternative form-factor, to be thin and light”, explained Sean Fitzgerald. “Initially the intention was for front-of-house type users in hospitality, retail – those sorts of places. But actually, we’ve seen since launch that managers, often, or supervisors – where they are coming into contact with either an office environment, or, particularly, with customers and clients – they don’t want the old, conventional, chunky form-factor.
“It’s fully featured, so it meets all of the DMR functionality that our standard radios meet, apart from that it’s digital only. All of our other MotoTrbo radios are dual analogue and digital, but to help with the miniaturization of this one, it’s digital only, and it’s reduced power – it’s only two watts. It’s primarily intended for indoor use. But the sensitivity is higher as well, so actually the range reduction is not so much as the power reduction would imply.”
For applications which involve job-ticketing, Motorola has included a five-line colour display which can convey more information than the usual two or four-line radio display. Other features are built-in texting, with pre-programmed or free-form messages, a shortened antenna which makes the radio look more like a mobile phone, and Bluetooth.
“We’ve got our own specialized Bluetooth earpieces which are intended for faster PTT response, but you can use just a standard, off-the-shelf earpiece”, Mr Fitzgerald adds.
Getting priority access to an LTE network
Following demonstrations of a hybrid Tetra/LTE system for mission-critical users at last May’s TETRA World Congress, Alcatel-Lucent showed a further refinement of the technology at PMR Expo. “We are showing the impact of quality of service on transmitting video”, explains Jérôme Brouet. “Here we have two live cameras connected to two LTE terminals. One terminal is configured without quality of service [management], using best effort; and one terminal is working with configured quality of service.”
When the network is uncongested, both halves of the big screen show clear pictures relayed from a nearby camera. But as M Brouet loads up the network with simulated data traffic, the picture starts to change. “You see that the video without quality of service is going into blocks and it’s freezing. We also see that there are time-outs. We’ve put some ping windows here and you can see that packets did not go through.”
Meanwhile, on the QoS side of the screen, the video stream plays on without degradation. “It’s a demonstration to see how powerful the LTE toolboxes are to manage quality of service, priority and all of those type of things, so that you can actually decide which flow, when there is an incident to manage, is the flow to put priority on”, he says. “An LTE bearer is established end-to-end and each LTE bearer has specific quality-of-service rules. Those rules are populated in the base station, in the core network, everywhere in the LTE network.
“And those rules are pre-configured in another element of the LTE, which is called the PCRF [Policy, Charging and Rules Function]. You populate the rules there and you can modify the rules when you want.
“Let’s say you have default settings for all your first responders – so they have all equal priority, they have different levels of quality of service for different applications that they have access to. And then if there is an incident, maybe you want to dedicate a Team A and a Team B to this incident, but not Team C. But Team C might be in the same location as Team A and Team B.
“So you will change the settings of those teams. You might have templates present to ease the process in the command and control room, to load new rules to this PCRF that I mentioned before. And then the rules can be populated to the different equipment in the LTE network.”
In this way, the rules can be changed dynamically to give team A and team B priority over Team C. “I think this is one of the powerful things of LTE, on top of throughput, latency and so on”, M Brouet adds.
Serving video to first responders
Relaying live video at the scene of an emergency will be a task for LTE, but tools for displaying and using video will also be needed. A solution developed by Alcatel-Lucent uses a central server to manage multiple video sources and destinations.
“The equation we had to solve here was a three-dimensional equation”, explains Jérôme Brouet, of the company. “The first one was how to minimize the consumption of radio bandwidth when you want to transmit multiple video information to somebody in the field, because video is quite bandwidth-consuming.
“The other thing is that when you are having mobile devices – smartphones, tablets, whether they are ruggedized or not – they have limited capabilities in terms of processing, especially when it comes to displaying video information. The CPUs and the graphical processors that are there are capable of handling one flow, but when you have to decode multiple flows at the same time they usually fail. That’s the second dimension of the equation we had to solve.
“And the third one was – when you have video, what do you do with it? Why can’t you share videos between people?
“So what we do is we have a client/server solution whereby most of the processing is done remotely. Here we have an example of an application where we show four different streams. It shows us four different, independent streams on the screen, and the end user can manipulate them as if it were a single stream – so you can zoom in, zoom out or whatever. But in terms of the flow that is sent to these tablets, it is actually one video flow – but it displays like it was different video flows.”
In addition, a first responder on the ground can select one of the incoming video streams and share it with his team.”
Portable Tetra infrastructure for a quicker deployment
On the Cassidian stand, visitors saw demonstrations of temporary Tetra radio coverage for applications such as disaster relief, based on the company’s growing range of transportable infrastructure. A portable Tetra switch, the DXT3p, was unveiled at the show.
The demonstration system included a TB3p transportable Tetra base station linked by an E1 cable to a satellite modem and Ku-band uplink dish, from which the connection was relayed via a geostationary satellite to a DXT3 Tetra switch at Cassidian’s engineering base in Ulm, Germany. To complete the loop, an ISDN circuit from Ulm was connected to another Tetra base station placed on the other side of the stand, enabling exhibition visitors to try the satcom-linked end-to-end connection for themselves.
“The customer can, via these two units, obtain a feeling of how Tetra works”, explained Markus Weber, of sister company EADS Astrium. “There are slight delays, so the customer can get the feeling of what the delay is. It’s roughly half a second.
“There was a large amount of talk of how far one can live with that delay, and this system will work without delay. We did some tests beforehand with our colleagues from Cassidian and we could then demonstrate that it’s OK and it’s acceptable. That’s why we decided to demonstrate it here as well.”
IP links for radios and data
Showing a range of remote links for controlling analogue and digital radio was André Wohnig, of Thiesen Hardware Software Design in Germany. “We have remote radio control over IP so we can use the IP network”, he said. And he added: “The biggest IP network is the Internet, so we can use the Internet too.
“Additional to the data transfer from the RRC (remote radio control), we have these Tetra/Tetrapol adapters. We can use Tetra radio to transfer the data and the voice over an IP network. So we can have a Tetra radio on top of a mountain and the user interface down the bottom of the mountain.”
Also offered are converters for serial and parallel data links.
A simpler route to digital with dPMR
Manning the dPMR Association’s stand was Malcolm Lyman, who works for the chip developer CML, one of the association’s member companies. “It’s growing all the time”, he said. “I think there’s about nine manufacturers now making dPMR, and it’s in direct competition to DMR.
“It is a simpler system, and the idea is it’s lower-cost and easier to implement than DMR, and it doesn’t have the IPR [intellectual property rights] costs of DMR. That’s why a number of companies are moving into it. I notice there are a few here – Kirisun, Kenwood, Icom have all got equipment on show here.
“Analogue manufacturers today, they have to make a choice, really, of Tetra, DMR or dPMR. Tetra is quite a complicated system and expensive, with a big learning curve; DMR is the next layer down, and that has also quite a large learning curve – whereas dPMR is a much simpler system to implement. However, it still offers the same functions – it offers peer-to-peer, Mode 2 and trunking.
“There is an overlap with DMR and some manufacturers are going that way and some are going this way. It’s a bit difficult for CML, in a way, because we represent both! We have chips that are representing both DMR and dPMR – and Tetra – so we have chips in all those systems!
“One of the things about dPMR is that the backward compatibility to analogue is an advantage.
“It’s much easier to make an FDMA radio flip between 6¼ kHz digital and 12½ kHz analogue, whereas a DMR radio has got to flip between two-slot TDMA and analogue; it’s a bit more difficult. But then we have the chip for DMR as well!”
DMR Tier III dispatching
Among Tait’s collaborators in its Tier III DMR trunking programme is Zetron, whose DMR dispatch software was demonstrated on the Tait stand. “It’s connected via IP ethernet, through our node switching”, explained Christine Cant. “Basically this is very configurable, but at the moment we’ve configured it up so that we can do talkgroup calls, individual calls.... You can also dial them. You can do a radio check, which is just asking whether the radio is turned on. You can do a short text message, which is a 50 character text to the radio, and status messages, which are pre-programmed. You can stun and revive the radios: say, if you’ve detected maybe that a radio has been stolen, or with the AVL solution you can see that it’s disappeared off the radar, you can stun it so that it can’t be used.”
In addition, she said, there is great flexibility for patching calls across multiple networks – for example, a DMR network could be patched through the console to a Tetra network. “A lot of people want gateways, so they want full functionality, but you can do it through a dispatch.”
Since the dispatching package is all-IP, it can support multiple control rooms at multiple locations. For smaller, less complex DMR networks, Zetron offers an alternative system which can be as simple as a desktop dispatch terminal. “It’s all using the open interface standard that has been ratified by the DMR Association and written into the ETSI standard”, Chris Cant continued. “It’s an open protocol that all manufacturers use.”
Mixing Tetra with cordless phones
With an upgrade to the alarm location server from Funkwerk Security Communications, DECT cordless phones and Tetra radios can be combined on the same server, with cross-messaging. Dietmar Schöps explains that the combination can suit workplaces such as pharmaceutical plants where Tetra radios are used out on the plant but pocket-sized DECT devices may be more convenient for workers in laboratories or offices.
“On the DECT phone you usually have messaging to alarm people, but if you need a verbal group communication, then you move to Tetra”, he says. “And as both technologies are using the same indoor localization beacon and the same type of messaging and the same application server, those two technologies can be combined. So if you move into a building with your Tetra terminal, you are located with the beacons which are usually used for the DECT phones which are inside the building.
“In an alarm scenario, you send messages to both, and for the alarm server and the person who is dealing with the alarm it appears as one system. Even if you have a certain group in mind, which is gathered from Tetra terminals as well as DECT, you get the responses back from both.
“You can create a message on the DECT phone and send it to a Tetra terminal and both technologies provide a connection to the PABX so you can talk between the systems. You can have a group conversation between the systems, so it’s seamless – both technologies integrate seamlessly. Including, as I said, messaging means you can use the DECT system also for telemetry applications. It need not necessarily be a Tetra radio.”
The alarm server also handles responses to emergency calls. “What we have here is the so-called warning alarm, which is very much used in hospitals or elderly homes to ask for help”, Mr Schöps continues. “If you are in a situation which you cannot do alone, you simply press that button. The alarm server will inform other nurses and the one who takes it retrieves the alarm from the others. So you know that this one has been taken and you don’t have to care for it any more. That can be done with DECT and Tetra in parallel. If somebody on a DECT phone takes the call, it disappears from the Tetra terminal as well.”
Assuring a quality PMR service for all
A unique maintenance aid for radio site operators was shown by the Australian antenna specialist RFI. “It measures the output power of individual transmitters after the transmit combiner”, explained Kevin Booker. “We put a decoupler in the coaxial cable line going from the combiner to the antenna and we sample off that.
“We program this with each of the frequencies, we program an upper and lower power limit, and upper and lower VSWR limits, and also an insertion loss limit. So as the transmitter transmits, part of that signal is passed through the monitor. The monitor goes to its look-up table, has a look at the frequency, has a look at the parameters – and if the parameters are within the values that are preset, it simply allows it to go through.
“If it’s outside of those parameters, it gives you an alarm condition. And then you can go into it and you can remotely access it by TCP/IP or the Net, and then you can have a look at what the alarm condition is. Is it a high volts alarm? A low volts alarm? Then you can make a decision about what action you need to take.
“It’s unique in the fact that we are doing it per-channel after the transmit combiner. That takes the whole RF path into account. So you are looking at the power that is actually going to the antenna.”
Tier II compliant radio system to take away
New on the Hytera Mobilfunk stand was a portable, vehicle-mountable repeater, the RD 965. “It’s a DMR Tier II product with an output power of 10 W with a battery pack that facilitates eight hours of operation without the need for an external power supply”, said Markus Oltmanns. “You can take it with you – let’s say, in some crisis situation, or some area where you have an occurrence, like, on a mountain or in the woods, where you have an urgent need for a communication system. You can take it with you, place it somewhere, just switch it on and have a complete Tier II-compliant radio system working.”
With its rugged housing, the unit is also suitable for fixed operation. “It is IP67, it’s waterproof, it’s almost dust-proof”, Mr Oltmanns continued. “There’s no moving parts in it like fans, so you can just mount it to a wall and connect it to an antenna system. It has IP connection capabilities in order to build up a large network.
“With the battery pack it’s about 6 kg. The battery pack itself brings some intelligence with it. If you connect it to a power supply the battery will be charged if the repeater is in operation at the same, in order to make sure that the repeater or the battery pack itself is usable at any time.
“We have a GPS connector in order that you can monitor the location of the mobile system. So if you use it in the woods or on the mountains, you can connect it to a dispatcher application so you can easily locate the equipment itself. You can also use the repeater as a radio.”
Also on display were the company’s Accessnet DWS touch-screen dispatcher application for Tetra systems and, making its debut, the SmartDispatch system for DMR. “We have even more features than with the Tetra dispatcher”, Mr Oltmanns said proudly. “We have a dispatch area which can be seen here for calls to the telephone network, we have calls to the radio network. We have GPS localization and geo-fencing already included: this screen area is an allowed area and you can also define forbidden areas. So if the subscriber enters a forbidden area, he will have an alarm. Messaging is already included, as you can see here – status messages, for example. This is the main difference to the Tetra dispatcher: this is the voice recorder already included.
“We have a report area where you see everything that is happening within the radio system. You can see the call type, start time, duration, who is calling. You can easily select them, press a playback button and you can listen in after. You can export files on an external hard disk, for example, and for countries where you are not allowed to track or record these details, you can disable it by a software key.”
An extra half a slot for digital users
Tetra, dPMR and DMR are not the only routes to digital for PMR users. A further possibility is the so-called e-DMR system developed by the French manufacturer Detracom. With its TDMA time-slotted transmission format, this is similar to DMR except that it has what might be seen as 2½ time-slots instead of just two. The extra half-slot is used as a control channel, enabling the two traffic channels to be operated independently.
In France, the system has proved attractive to users in the public utilities who hold low-band spectrum assignments, a band for which other digital technologies are not available.
“The users are people who need large geographical coverage but they need data communications at the same time as voice – for example, electricity companies, security forces”, says Serge Huc, managing director of Detracom. “They are very, very numerous. Our core market is low band, where there are many analogue networks and these users thought they would have to change to UHF, at a large increase in site costs. When they discover e-DMR, they all go, ‘It can’t be!’ And when they see it working, they say it’s marvellous!”
“At present our system is a single-channel system but we are working on the specifications of a trunked e-DMR system. The spectrum efficiency of our system is very good because two of our RF channels are equivalent to six channels in MPT 1327.”
Detracom is continuing to developing e-DMR technology to add new capabilities – an automatic terminal tracking system is among the latest. “Low band users are everywhere, and for now this niche is enough for us to grow”, M Huc says. “We are in discussion with other manufacturers for them to adopt e-DMR technology, so we are not alone any more. We truly believe that we don’t have to remain alone with this technology. Maybe in the future you will find multiple manufacturers – different manufacturers that will sell more and more networks.”
Cutting the PMR cord
Many PMR systems do not provide handportable coverage, leaving users unable to communicate when away from their vehicle. An innovative solution to this problem is the X10DR (pronounced ‘Extender’) wireless speaker-microphone, from Wireless Corporation in Hong Kong.
“What X10DR does is to provide a very low-cost way for the user to get 300 metres coverage around their vehicle”, explains Martin Cahill. “So two police officers can have two of these connected to one mobile and they can talk to each other, or in an ambulance you have three – the driver and two paramedics.
“Predominantly, people are out of their vehicles 70 per cent of the time – so if you pay all this money to put in a system and then you can’t talk for 70 per cent of the time, it’s a big investment. So we think this is a great way of providing that link back. Basically we took the microphone off the dash, cut the cord and allowed the users to walk around.”
Operating in the 2.4 GHz ISM band, the microphone employs a variation of Bluetooth technology. With a Class 1 radio and a ground-independent antenna in the handheld unit, it provides up to 300 metres range. A multi-polarity antenna for the vehicle is claimed to provide up to 5 dB better performance in multipath situations. Mr Cahill points out that standard Bluetooth is not ideal for two-way radio systems because of the requirement for instant press-to-talk, and the company had to develop a number of enhancements to the 802.15 protocol to make it suitable.
“Of course, the other thing today is occupational health and safety and duty of care for lone workers”, Mr Cahill adds. “It’s the employer’s responsibility to make sure that staff are safe when they get out of their car and X10DR is a great way of providing that communication.”
Ringing the changes on speaker-mics
With some 50 standard products and as many as 1800 variations on them, the German radio accessories manufacturer Imtradex has the flexibility to meet an exceptionally broad range of user needs.
“Four or five years ago, in groups with users, we found out that they are turning to digital radios but they didn’t know what they wanted to do in the future”, said Ralf Kudernak, managing director and co-founder of the company. “We found out that when they worked with digital radios, they got new ideas about what they can do – and we said, when we develop a product, we must be so open that later on we can have different knobs on it or we can have our display and so on, so that we can improve the product. At Imtradex, we always try to find an economic solution.”
Latest of these is a robust Bluetooth speaker-microphone designed to work with the latest Bluetooth-enabled digital PMR units as well as with mobile phones.
Distance and diversity
Also present at the show was the Tetra infrastructure manufacturer 3T Communications, once a part of Frequentis but owned since last May by Sepura, and now appearing for the first time under its new branding.
“We offer Tetra infrastructure – base stations for small systems like this solo one, or bigger ones with up to eight carriers for airports, or whatever”, said Erich Pfaffelmayer, of 3T. “We do networks starting from single site up to multi-site with hundreds of base stations. We are strong in the commercial market, especially, for example, in power utilities. We have a lot of offshore projects; we do local government, including public transport, and a lot in industry like oil and gas, with intrinsically-safe radios. This is one of the common cases where we can use the Sepura terminals.”
A speciality of the company is its skill in exploiting some of the lesser-known features of Tetra. For example, it offers long-distance Tetra, for uses such as air-to-ground communication with rescue helicopters. “This means that we can communicate further than about 50–60 km, which is normally the limit due to the Tetra coded signals”, Mr Pfaffelmayer said. “We did, for example, tests in Iceland with a distance of about 115 km – provided there is line of sight, of course! It’s reducing the header to allow longer distances.”
Another special feature he highlighted is the digital equalizer built into 3T’s Tetra base stations, which enables them to deliver good reception even amid problems with signal reflections. “Normally if there are reflections, the signal is phase-shifted – and if you add two signals which are phase-shifted, you lose quality. But with an equalizer you can arrange that the shifted signals are synchronized, and then you gain a better output. I think our base station is the one and only in the market using an equalizer on top of diversity. It is an improvement – 2 dB or something like that on top of diversity and sometimes every decibel counts.”
Latest Tetra handheld radio from Sepura, the STP9000, embodies a series of innovations – of which the most striking is its haptics (touch sensation) feature. The aim is to provide better keypad feedback for users – especially those in public safety who frequently wear gloves. “We’re taking some of the technologies that have been introduced into mobile phones and PDAs and moving that on to PMR radios, specifically with functionality that meets demands and requirements of our users”, explained Kasper Barfoed.
“Secondly, this radio is IP67 classified, so basically you can take it under water, one metre down, and leave it there for about five minutes. I wouldn’t be very worried if you left it there for, let’s say, an hour, and it would probably still work. So it really is completely waterproof, and it has the highest IP classification of any handheld Tetra radio in the market today – including Atex radios.”
Furthermore, he went on, in the STP9000 Sepura has introduced a choice of three contrasting user interfaces. While the company had remained true to the traditional PMR user interface with a ‘flat’ menu structure, devices such as PDAs and smartphones had now familiarized users with more complex menu structures where they would expect to dig deep to find some of the functions they needed. By altering the installation options, the user can choose from three user interfaces, including a familiar mobile phone-like configuration.
“Not only are we offering this choice but we let the administrator of the fleet decide whether they choose what interface to give the individual user, or whether the user can choose by himself”, Mr Barfoed said. “The important thing here is that, irrespective of what user interface is chosen, the functionality stays exactly the same. And the way the radio operates in the network, which is something which is very much key for any operator of a secure network, it doesn’t change its behaviour, it doesn’t change what capacity load it places on the network.”
Another new Tetra terminal announced by the company was a full keypad version of its intrinsically-safe handheld radio, supplementing the simplified keypad version which has been available since March. “We are getting very close to having shipped about 10 000 of these things”, commented Mr Barfoed.”These radios are certified to the very latest Atex standard, which is called Version 6 of the Atex standard. And there’s not another product that is certified to that – which, incidentally, includes any accessory that we put on to the radio. It needs to be certified with the radio, so when you walk into these hazardous environments, you can be sure that everything you’ve got is certified – which wasn’t required before.
“It’s going to mean an additional investment for customers because everything has to be certified and everything has to be Atex, but it does add security and it does have implications regarding insurance.”
Also featured on the stand was STProtect, an indoor location product developed by Sepura for lone workers. Designed for use in environments such as prisons or mines where GPS location is not available, it relies on compact radio beacons installed at key points. Coverage range of the beacons can be adjusted from 10–20 metres down to very short distances, to deliver the required positioning accuracy. The system supports defined routes and checkpoints for security guards, access control for gates and doors, and man-down features.